可逆形成的CN键在动态共价化学中起着非常重要的作用,并且在不同亚胺成分之间组分的CN/ C exchangeN交换以创建动态共价文库已被广泛使用。为了促进多样性的产生,我们研究了一种有机催化方法,使用L-脯氨酸作为催化剂,以加速[ n × n ]亚胺组分动态库的形成。在某些条件下,有机催化方法也已扩展到巴比妥酸的Knoevenagel衍生物和亚胺之间的可逆CC/CN交换过程,从而增加了多样性。
Diazoketones as precursors in β-lactam synthesis. New insights into the mechanism of the photochemically induced Staudinger reaction
作者:Michael R. Linder、Wolfgang U. Frey、Joachim Podlech
DOI:10.1039/b105748k
日期:2001.10.11
Diazoketones 1â3, derived from suitably protected amino acids (Ala, Val and Tle), have been photochemically rearranged in the presence of imines leading exclusively to trans-arranged 4-aryl- and cinnamoyl-substituted β-lactams 17â33 with up to 84% yield. Selectivities were dependent on the steric demand of the amino acid side-chain ranging from 65 â¶ 35 to 90 â¶ 10. The relative configurations were proved by several X-ray crystal structures and comparison of NMR spectra. Further reactions of the azetidinones at position C-4 have been performed: electron-rich aryl substituents (e.g., 4-methoxyphenyl, furyl and thienyl) could be degraded to carboxylic
acids 34 and 35 which were further transformed to acetoxy derivatives (compounds 36 and 37) in a Kolbe reaction of type II. The cinnamoyl group could be oxidized to the formyl group by ozonolysis (â
38, 39). The mechanism of the photochemically induced β-lactam formation is discussed in detail.
[EN] MANGANESE BASED COMPLEXES AND USES THEREOF FOR HOMOGENEOUS CATALYSIS<br/>[FR] COMPLEXES À BASE DE MANGANÈSE ET LEURS UTILISATIONS SERVANT À UNE CATALYSE HOMOGÈNE
申请人:YEDA RES & DEV
公开号:WO2017137984A1
公开(公告)日:2017-08-17
The present invention relates to novel manganese complexes and their use, inter alia, for homogeneous catalysis in (1) the preparation of imine by dehydrogenative coupling of an alcohol and amine; (2) C-C coupling in Michael addition reaction using nitriles as Michael donors; (3) dehydrogenative coupling of alcohols to give esters and hydrogen gas (4) hydrogenation of esters to form alcohols (including hydrogenation of cyclic esters (lactones) or cyclic di-esters (di- lactones), or polyesters); (5) hydrogenation of amides (including cyclic dipeptides, lactams, diamide, polypeptides and polyamides) to alcohols and amines (or diamine); (6) hydrogenation of organic carbonates (including polycarbonates) to alcohols or hydrogenation of carbamates (including polycarbamates) or urea derivatives to alcohols and amines; (7) dehydrogenation of secondary alcohols to ketones; (8) amidation of esters (i.e., synthesis of amides from esters and amines); (9) acylation of alcohols using esters; (10) coupling of alcohols with water and a base to form carboxylic acids; and (11) preparation of amino acids or their salts by coupling of amino alcohols with water and a base. (12) preparation of amides (including formamides, cyclic dipeptides, diamide, lactams, polypeptides and polyamides) by dehydrogenative coupling of alcohols and amines; (13) preparation of imides from diols.
Sustainable iron-catalyzed direct imine formation by acceptorless dehydrogenative coupling of alcohols with amines
作者:Garima Jaiswal、Vinod G. Landge、Dinesh Jagadeesan、Ekambaram Balaraman
DOI:10.1039/c6gc00565a
日期:——
The Acceptorless DehydrogenativeCoupling (ADC) of alcohols with amines is reported using a heterogeneous Fe-catalyst.
据报道,使用非均相铁催化剂,醇与胺的无受体脱氢偶联(ADC)。
Ionic Liquid Promoted Aza-Diels-Alder Reaction of Danishefsky’s Diene with Imines
作者:Giang Vo-Thanh、Bruce Pégot
DOI:10.1055/s-2005-869837
日期:——
A highly efficient procedure for the synthesis of 2-substituted-2,3-dihydro-4-pyridone derivatives through the aza-Diels-Alderreaction under 'green chemistry' conditions is described. The reaction of Danishefsky'sdiene with imines has been found to perform better at room temperature in ionic liquids without an acid catalyst and organic solvent: the ionic liquids are recycled while their efficiency
The combination of Et2Zn and RhCl(PPh3)3 led to the facile generation of a rhodium–hydride complex (Rh–H) that catalyzed the 1,4-reduction of α,β-unsaturatedesters. The resulting rhodium enolate performed as a Reformatsky-type reagent and reacted with various imines to give syn-β-lactams in good to excellent yields with high diastereoselectivity.
Et 2 Zn和RhCl(PPh 3)3的组合导致容易生成铑-氢化物络合物(Rh-H),该络合物催化α,β-不饱和酯的1,4-还原。所得的烯醇铑作为Reformatsky型试剂起作用,并与各种亚胺反应,以良好的非对映异构体收率以优异的产率得到合成的-β-内酰胺。